pypy3: use valid pypy3 path in src_install

Set $PYTHON to a known existing path for pypy3-c instead of a broken
symlink. The PYTHON env var is used by python_optimize to
determine the path of the python implementation used to compile all the
standard libs, and if the path is broken, .pyc files don't get
generated.

More information about the underlying issue and potential fixes is
available at http://shortn/_kP8nkDxu58.

BUG=b:201487405,b:187793277

Does this CL fix the root cause of b:201487405? Run a tryjob with the
reland CL and the fix (this CL).
TEST=`cros tryjob --remote -g 3198893 -g 3232964 chromiumos-sdk-tryjob'
passes (YES) - https://ci.chromium.org/b/8832892772655764145 (patchset
2), https://ci.chromium.org/b/8832746527699544177 (patchset 3)

Does this CL not break the SDK as-is? Run a tryjob with this CL.
TEST=`cros tryjob --remote -g 3232964 chromiumos-sdk-tryjob' passes
(YES) - https://ci.chromium.org/b/8832900189125341057 (patchset 2),
https://ci.chromium.org/b/8832746507744530785 (patchset 3)

TEST=CQ

Cq-Depend: chromium:3198893
Change-Id: Ia80c6086293b7f74a78fed8ec5bebc38189ba4d5
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/3232964
Tested-by: Lizzy Presland <zland@google.com>
Auto-Submit: Lizzy Presland <zland@google.com>
Commit-Queue: Lizzy Presland <zland@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
1 file changed